Outside, the weather is cold and gloomy. You’ve had a long, hard day at work and you’re just longing to get home and put your feet up in a nice and cosy living room.
The problem is, and you’ve probably noticed this for some time, that although in some rooms, usually the bedrooms, the temperature stays nice and comfortable, other rooms maintain something of an unwelcoming coldness. The radiators just don’t seem to get hot enough.
You’re fairly confident that the wet central heating system pump is operating correctly and that you’re not trying to run more radiators than the system was designed to accommodate. You’ve probably also tried bleeding each radiator to ensure there are no air locks.
So, what is most likely to be the problem?
It is most likely that your radiators require balancing.
Don’t despair, there is a relatively simple procedure that will confirm that incorrect balancing is the problem and that will also significantly improve the situation.
The first thing to do is to establish the direction of flow and return to and from the boiler.
Conventionally, in a multi storey dwelling, the central heating system will be installed to take advantage of the fact that hot water rises. This is to aid the efficiency of the system pump.
So the first radiator on the system is likely to be in an upstairs bedroom.
The easiest way to find out the sequence of the flow through the central heating system is to turn off the boiler and let the radiators go cold. Once this has happened, turn the system back on and follow how and when each of the radiators heats up as the hot water starts to re-circulate. It would help if you can get some assistance from other household members or friends stationed at each radiator to confirm the order in which the radiators reheat. Don’t forget that you may have a heated towel rail in the bathroom as part of the system.
In a single storey dwelling, the first radiator will most likely be the one nearest to the boiler and heating pump.
There is no need to turn the heating system off for the following procedure.
Having located the first radiator in the system, return to it.
You will notice that there are two pipe work connections to the radiator. One usually near the top which controls the flow into the radiator. It will be a white tap which can be turned on or off and in some cases may have graduated or numbered position markings.
Ensure that this valve is turned fully on.
Next, turn your attention to the outlet valve at the base of the opposite end of the radiator.
This is known as the lock shield valve.
It should have a white cap on it. This cap may be secured by a central screw which will need loosening before the cap can be removed.
After removing this cap, you will find the valve which is operated by turning the square ended brass spindle that you have exposed.
Using a spanner or set of pliers and taking care not to burr the spindle edges, turn the spindle clock-wise to fully close the valve.
Now turn the spindle a quarter turn anti-clockwise to partially open the valve.
Move on to the next radiator and repeat the process but this time when you partially open the lock shield valve, give it a half turn anti clockwise.
Continue working through the rest of the radiators sequentially increasing each lock shield valve turn by one quarter. By the time you reach the final radiator on the system, the lock shield valve should be fully open.
Give the system time to stabilise and then check the formerly cooler radiators to see whether they are now hotter.
If they are, then balancing will have been the issue affecting your system.
The improvement you have achieved may be satisfactory for you, and if that is the case, then the task is completed. Don’t forget to ensure that the lock shield valve caps have been replaced.
However, if this has not remedied the situation, the problem probably lies elsewhere and I would recommend sourcing additional advice.
If balancing has resolved the problem, then you may wish to consider having your system’s balancing finely tuned. This is a slightly more complex procedure which requires a dual thermometer. The process aims to achieve a twelve degree centigrade drop in temperature between each radiator’s inlet and outlet valve standardised across the system.
By fine tuning the system, the efficiency of the central heating system can be improved, but as efficiency is dependent upon a variety of contributing factors, it would be better to ensure that the whole central heating system is periodically serviced by a qualified and competent operative.
However, a combination of simple home maintenance procedures carried out by the householder along with a comprehensive service programme, will ensure that a reliable, energy efficient and robust system operates to keep your home warm during the coldest of weathers.